Sheet feeding means



Feb. 24, 1970 H. HARRISON 3,497,205

SHEET FEEDING MEANS Filed Sept. 7, 1967 3 Sheets-Sheet 1 FIG 2 FIG 3INVENTOR.

HENRY HARRISON gw'p-Walmg Feb. 24, 1970 H. HARRISON 3,497,205

v SHEET FEEDING MEANS Filed Sept. 7, 1967 3 Sheets-Sheet 2 INVENTOR.

HENRY HA R RISON Feb. 24', 1970 H, ARRlSoN 4 -s',497,2os

SHEET FEEDINr MEANS Filed Sept. 7, 19s? s Sheets-Sheet :s

FIGS

INVENTOR.

HENRY HARRISON yaw M M United States Patent 3,497,205 SHEET FEEDINGMEANS Henry Harrison, Locust Valley, N.Y., assigncr to Halm InstrumentCo. Inc., Glen Head, N.Y. Filed Sept. 7, 1967, Ser. No. 666,150 Int. Cl.B65h 1/06, 1/24, 3/06 US. Cl. 27141 3 Claims ABSTRACT OF THE DISCLOSUREThis invention relates to feeders for automatically delivering sheets,envelopes, cards, thin plates, or the like (hereinafter calleddocuments) from a stack to a processing machine, for instance, aprinting machine.

There are well known advantages in taking documents from the bottom ofsuch a stack, especially the advan' tage that the stack can bereplenished without interrupt ing the feeding process. Another advantageis the mechanical simplicity which results from having the next sheet tobe fed always in the same position in the stack as its predecessor.

A major disadvantage of bottom feeders is that the frictional resistancewhich must be overcome in taking a sheet from the bottom of the stackdepends on the weight, and therefore on the height of the stack aboveit.

In a high speed machine such as a high speed printing press, a smallstack of documents runs through in a short time. It frequently happensthat the stack must be replenished at inconveniently short intervals,and therefore many expedients have been tried to increase the maximumheight of a stack which could be fed. Prior to this invention, however,the maximum stack height has always been limited by the force whichcould be exerted by the feeder mechanism on the document, in separatingit from the stack and moving it, against the frictional resistance ofthe weight of the stack, to the place where it is firmly gripped fortransfer to the subsequent operating station.

The invention to be described was developed in conjunction with anoscillating vacuum sucker feeder such as in US. Patent No. 2,770,458. Inthis high speed feeder, which operates in excess of 60,000 documents perhour, the documents leading edge is sucked down against a cylindricalsucker, and then moved forward, by friction with the sucker, intoengagement with driven spring loaded pinch rollers, which positivelydeliver it to a printing press. The force which this system can exert onthe document for transferring it into engagement with the pinch rollersis necessarily limited by the active area of the vacuum sucker, and thegripping force per unit area exerted by the atmosphere, but the forceexerted by the pinch rollers on the document is limited only by the tearstrength of the document.

Another feeding mechanism commonly used is the pick type feeder in whichthe trailing edge of the document is engaged by short hardened picks,short enough to engage only a single document, and propelled forward bythe picks into engagement with a pair of pinch rollers. During theportion of the cycle when the picks are moving the document to thepin-ch rollers, the maximum force which can be used to overcome thefriction of the weight of the stack is limited by the crushing orbuckling strength of the edge of the document.

It is the primary purpose of my invention to provide a means forrelieving the bottom document of a stack from the weight of the stackduring the time that it is being transferred into engagement with pinchrollers or grippers, so that much higher stacks of documents can be fed.It will be evident to those skilled in the art that my invention can beapplied not only to the two types of feeders referred to above, but alsoto many other kinds of document feeders which deliver documents from thebottom of a stack. Other objects and advantages of my invention, such assimplicity, freedom from adjustment, improvement of registry, andothers, will be evident from the following description, which should beread in conjunction with the accompanying drawings.

Accordingly a principal object of the invention is to provide new andimproved means to feed sheets from the bottom of a stack.

Another object of the invention is to provide new and improved means tofeed sheets from the bottom of a stack comprising means to lift saidstack in synchronism with said removing means.

Another object of the invention is to provide new and im roved means tofeed sheets from the bottom of a stack and means to take the weight offsaid bottom sheet while said bottom sheet is being removed from saidstack.

Another object of the invention is to provide new and improved sheetfeeder of the type having means to feed sheets from the bottom of thestack, means to take the weight of said stack off the bottom sheet ofsaid stack while said bottom sheet is being removed, and means tosynchronize said feeding means and said weight re moving means.

These and other objects of the invention will be apparent from thefollowing specifications and drawings of which:

FIGURE 1 is a side view of an embodiment of the invention.

FIGURES 2 and 3 are side views illustrating the sequence of operation ofthe embodiment of FIGURE 1.

FIGURES 4 and 4A are detail views of an embodiment of the invention.

FIGURE 5 is a side view of a modification of the invention.

FIGURE 1 is a schematic drawing of a feeder of a vacuum sucker typeembodying my invention, showing the leading edge of the bottom documentdrawn down against the sucker.

FIGURE 2 shows the feeder of FIGURE 1 as the sucker advances thedocument into engagement with the pinch rollers.

FIGURE 3 shows the feeder of FIGURE 1 as the pinch rollers deliver thedocument to subsequent stages of the machine. FIGURE 4 shows details ofa feeder of the vacuum sucker type embodying my invention. FIG- URE 5shows the application of my invention to a feederof the pick feedertype.

Referring to FIGURE 1 the stack of sheets 12 rest on platform 24 and isconfined by the guides 14, 16, 18, and 20 which are suitably mounted tothe frame of the machine. The platform 24 is oscillatably mounted bymeans of the parallelogram linkage comprising the members 46, 48 whichare pivotally mounted to the platform 24 at one end and pivotallymounted at the other ends to the lever 50. The lever 50 is pinned at itsright hand end to the lever 44 which is pivotally mounted to the frame Fat its upper end. On the other end of the lever 44 is mounted a camfollower 42 which bears against the cam 40 which is rotatably mounted inthe frame F on the shaft 40. On the other end of the shaft 40 is mountedanother cam 30 which operates cam follower 32 which is mounted on thelever 34 which is pivotally mounted on the frame by means of the shaft34'. A member 8 is pivotally connected to the member 34 at one end andpivotally connected to an extension arm 36 which is fixedly connected tothe vacuum sucker 22. The vacuum sucker 22 is freely mounted on theshaft 22 so that it can oscillate. A first pinching roller 26 is mountedon the shaft 22' and is driven in a counterclockwise direction by meansof shaft 40, pulleys 38, 39 and belt or chain 37. Another pinchingroller 28 is pivotally mounted on the frame by means of the member 38'and is spring loaded against the pinching roller 26 by means of thesping 28".

Document is the lowest sheet of a stack 12, confined by guides 14, 16,18, and 20. Document 10, being sucked down against the cylindricalvacuum sucker 22, is curved, at its leading edge, ready to pass underthe lower end of guide 14, which will prevent the escape of the rest ofthe stack 12. Stack 12 is resting on the platform 24. Driven springloaded pinch rollers 26 and 28 are turning in the directions shown, butare not engaged with any document.

Turning now to FIGURE 2, document 10 is being advanced into engagementwith the pinch rollers 26 and 28 by forward counterclockwise oscillationof the vacuum sucker 22, which is oscillatably mounted behind roller 26on shaft 22. The advance of vacuum sucker 22 counterclockwise is causedby the cam 30 acting through the cam follower 32, levers 34 and 36, andthe tie rod 38, and therefore occurs in synchronism with the demand ofthe machine for delivery of a document at the same time. The platform 24is accelerated downward away from the stack, leaving the stack 12 in acondition of free fall, so that none of the Weight of the stack isresting on document 10'. The downward acceleration of platform 24 iscaused by cam 40, acting through cam follower 42, levers 44, 46, and 48,and tie rods 50 and 52. Since cam 40 and cam 30 are on a common shaft,the motion of the platform 24 is in synchronism with the motion of thesucker 22.

In FIGURE 3, document 10 is being positively drawn out from the stack 12by the action of the pinch rollers 22 and 28. The stack 12 is againresting on the platform 24, which is moving back to its initialposition. The remainder of the stack is prevented from escaping by thebarrier guide 14 and by friction with the platform 24. The sucker 22 isreturning to its initial position, and document 10 is sliding over itssurface. When document 10 uncovers the ports of the sucker 22, the nextdocument of the stack 12 will be sucked down, ready for delivery.

FIGURES 4 and 4A show details of a feeder of the vacuum sucker type,embodying this invention, which was constructed for feeding sheets ofpaper. The feeder is constructed on tiltable side frame 54, clamped tothe main frame of the machine, so that the stack guides 58 and 60 areapproximately 60 from vertical. This reduces the proportion of theweight of the stack resting on the movable platform 62. Barrier guides64 are provided at the leading edge of the stack, adjustably mounted ona plate 66 joining the two side frames 54. The shaft 78 of the sucker 80is journaled to the frames shown. Rollers 86 are mounted next to sucker80. These rollers have a diameter approximately equal to the diameter ofthe sucker 80.

To actuate the sucker, cam roller 100, riding in the groove of box camplate 102., moves arm 104, which is clamped to shaft 106 journaled tothe frame. Tie rod 110 joins arm 104 to arm 112, clamped to the suckershaft 78. Thus rotation of the cam plate 102 caused the sucker toadvance, moving the leading edge of a sheet of paper into engagementbetween the rollers and 86; and then to return to its standby position.Belts or other takeaway means are preferably provided to remove thesheets from and drive the punch rollers. To this point, the feeder issubstantially the same as the feeder described in Patent 2,770,458.

The improvement in the feeder of FIGURE 4 embodying the invention is themovable platform 62. Referring also to FIGURE 4A, this platform issupported on rollers 114 which roll in inclined grooves in blocks 116,116, and on an eccentric crank 118 clamped to the shaft 106. Thus whenthe sucker is advancing a sheet of paper, the platform is simultaneouslytraveling forward and downward beneath the stack. When the suckerreturns to rest position, the platform also return to rest position. Bysuitable choice of the radius of the eccentric crank 118, it has beenpossible to feed stacks of more than two thousand sheets of paper atrates as low as four sheets per second. Without the movable platform,reliable feeding of stacks of as many as five hundred sheets of paper isunusual.

In the feeder of FIGURE 4, the functions of cams 40 and 30 of FIGURE 1have been combined into a single cam 102. The levers 44, 46, and 48 arereplaced by the rollers 114 and the eccentric crank 118, and platform 62takes the place of tie rod 52. A strip of anti-friction material isfastened to the platform 62 near the back edge of its top surface, as bycementing on a strip of rubber. As it is returning up and back to restposition, the platform engages the bottom sheet of the stack, forcing itagainst the guides 58. Thus each bottom sheet is against the guides 58when the sucker cycle begins. As a result, successive delivered sheetsare in precise registry relationship with each other.

FIGURE 5 shows an embodiment of the invention in a pick type feeder.This type feeder pushes relatively stiff sheets off the bottom of thestack 80 by means of the pusher or pick 81 which is mounted forreciprocation on guide rod 82 and a corresponding rod, not shown, on theother side of the machine. The weight of the stack is supported by themembers 83, 84 which are pivotally mounted on the frame F by means ofthe pins 83', 84'. The forward edge of the stack is supported by theframe member F1 and the adjustable member F2 is adjusted in spacing fromthe member F1 to permit only one sheet to be pushed into contact withthe takeaway rollers 85, 86' which are continuously driven in thedirection shown by the arrows.

The lifting and dropping motion and the pushing motion is provided bythe linkage comprising the tie rods 87, 88, lever 89, cam 70 and camfollower 91 which rides in a groove 90 in the cam plate 70. The cam isdriven in the direction shown by the arrow. Therefore when the lever 80rotates clockwise due to the cam action, then the members 83 and 84 alsorotate clockwise and drop the stack and at the same time pusher 81 ispulled by the tie rod 87 so as to push the bottom sheet into :ontactwith the takeaway rollers 85, 86.

Many modifications may be made by those who desire to practice theinvention without departing from the scope thereby which is defined bythe following claims:

1. In a sheet feeder of the type having means to feed sheets from thebottom of the stack,

acceleration means to take the weight of said stack off the bottom sheetof said stack while said bottom 5 6 sheet is being removed comprising astack supportand toward the trailing edge of the sheets being fed, anding platform which is scinatable; down and toward the leading edge ofthe sheets being fed. rotary, oscillatable means located at the stackbottom for removing sheets; References Clted and means to synchronizethe timed driving of said 5 UNITED STATES PATENTS removing 11163118 whenI116 platform is accelerated 1 153 295 9 1915 Dunnebier 271 29 X awayfrom a stack support position. 2. Apparatus as in claim 1 wherein saidstack support- EDWARD A. SROKA, Primary Examiner ing platform is mountedon an oscillatable linkage.

3. Apparatus as in claim 2 wherein the direction of 10 oscillatablemotion of said stack supporting means is up 271 29

